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  1. #14
    Join Date
    Apr 2004
    Location
    Midwest
    Posts
    2,683
    I am using Carrier Comfort Zone II. With Carrier equipment there are several ways to achieve 4 stages of heat...does not have to be all done by the thermostat. But Carriers Thermidistat can do 4 stages of heat.

    Doc, I am just a little east of Akron...you were south of me by about 30 miles.
    Live each day like it is your last, for one day you will be right!

  2. #15
    Join Date
    Apr 2004
    Posts
    7,680
    Not you, I know where you live
    ..... I was talking about mopar

  3. #16
    Join Date
    Oct 2005
    Posts
    52
    Originally posted by docholiday
    Not you, I know where you live
    ..... I was talking about mopar
    LOL Yes, I do live in Wooster. Just outside of town.

    So as I figured, a 2 stage unit would be more for comfort than practicality or efficiency in my case.

  4. #17
    Join Date
    Oct 2005
    Posts
    52

    Thumbs up

    The contractor I plan on using was over tonight to do a manual J on my house. That is really interesting. I got complimented for doing my research & having a good idea of what I wanted & needed. His estimate on the furnace size was right on the money & was a half ton high for the h/p. I figured 2 1/2 ton by going by what others I asked have in their homes & I was right. It called for a 2.25 ton system, so we went with a 2 1/2 ton, 15 seer, single stage h/p. With the rebate on the Signature series units, it came out to be the same price as a 13 seer Elite unit w/no rebate. Hopefully this will all fly & we can get this put in.

    Thank you to all who take the time to give their knowlage & advise to this board. I do the same on some car boards. (former auto tech) This does a great deal to help all of us that want to be educated on what we are planning on buying. I'll post back later if I get this system put in, with some before & after pictures.

  5. #18
    Join Date
    Oct 2005
    Posts
    96
    Mopar Guy, we must be tracking together on this. Did you go with the HPXB15 heat pump. Did you go with the G61MPV high efficiency furnace? Given this combination did you go with the Signature Stat? With three steps of heat available you should be covered with two stages of gas heat and the other stage being the heat pump. You will also be able to take advantage of the humidity control available with the variable speed blower.

  6. #19
    Join Date
    Oct 2005
    Posts
    96
    As I mentioned I am taking BaldLoonies advice and shying away from the two stage compressorized heat pump. I presently have a 3.5 ton HVAC unit that is taxed on a 100 degree day in KC. I was planning to go to a 4 ton unit knowing I had the two stage compressor. Will this 1/2 ton cause me to be oversized and have potential humidity problems?

  7. #20
    Join Date
    Oct 2005
    Posts
    52
    Originally posted by ksspartan
    Mopar Guy, we must be tracking together on this. Did you go with the HPXB15 heat pump. Did you go with the G61MPV high efficiency furnace? Given this combination did you go with the Signature Stat? With three steps of heat available you should be covered with two stages of gas heat and the other stage being the heat pump. You will also be able to take advantage of the humidity control available with the variable speed blower.
    Yes, it looks like we're on the same page. I'm going with those two units as there is a rebate on both & the Signature stat. Yes, I'm going with the Signature stat, along with their 4" media filter & a new Aprilair humidifier. I wanted the Pure Air system but it's way overpriced (IMO), plus, it's expensive to maintain each year. My contractor has used all of this in his house & the last house he had & says with this set up, I'm better off with the Signature stat over the Vision Pro because of the same resaons you mentioned in the other post. I think I'll be pretty happy with this set up as it will fill my needs.

    Oh, BTW, have you had a Manaul J done on your place? If not, get it done before you go any further! That's the BEST advice on this board. It saved me from being almost 1 ton oversized. Offer to pay for it as I did & he was more than willing to do it. Since I'm going with him, he waived the fee for doing it.

    [Edited by mopar guy on 10-20-2005 at 09:00 AM]

  8. #21
    Join Date
    Oct 2005
    Posts
    96
    What do you mean by a Pure Aire System? Is this a Lennox system or another manufacturer? Why does it require more maintinance?

    Thanks for the advice on the Manual J. I think the first contractor that gave me a bid did one but he did it all by hand. I thought you needed a computer to do it? I will request that the contractor I am talking to on this Lennox system do one for me.


  9. #22
    Join Date
    Oct 2005
    Posts
    52
    I don't know if it's made by someone else. You need to change the UV bulbs, the catalyist & filter once which is about $400. I just felt it was to pricey.

    He didn't do one then. I had all the measurments for all the rooms in my house & it took about 45 mins to do. Believe me, it was worth it.

  10. #23
    Join Date
    Oct 2005
    Posts
    96
    Originally posted by BaldLoonie
    I think 2 stage super SEER units are overkill in cooler states like Ohio. I'm right next door. Often the high SEER doesn't mean high HSPF which is your winter efficiency. I'd look towards 12-13 SEER max for this area. You won't have comfort issues, just don't oversize the furnace or the heat pump. Make sure your dealer uses a dual fuel control that gives you 3 stages of heat if you get a 2 stage gas backup. More comfort than letting the timer in the furnace stage the fire.
    In states like Missouri does it make sense to oversize a heat pump, and install a two stage compressor that will typically always run only in the first stage during the cooling season and get the most capacity out of the heat pump during the winter? I don't want to get too fancy here and oversize my system so if the answer is to size the unit for the cooling season and get as much "free heat" out of the heat pump during the heating season I will go that way as I plan to use a dual source anyway (gas or electric).

  11. #24
    Join Date
    Mar 2004
    Posts
    1,042
    I wouldn't use a two stage unit as justification for oversizing. The ductwork probably won't like it, and with such low electric rates, the extra cost of the two stage unit won't pay for itself.

    Going from 3.5 to 4 tons isn't a huge difference. Depending on the condition and installation of the old unit, though, you may not be getting 3.5 tons out of it. Furthermore the manufacturers don't hit these capacity ratings spot-on... they round to half tons but in the end the capacities don't come out as tidy as you might think.

    What do you mean when you say that the system is "taxed" by 100 degree heat? Outside of the desert states, all air conditioners should run nonstop around the clock, or almost around the clock, in 100 degree weather. If they don't, it's a sure sign of oversizing, which results in inferior comfort and efficiency. Proper sizing builds in some recognition that there might be a couple days out of the year where you can't hold your temperature setpoint; you may slip a degree or two in the peak heat of the afternoon. If you add capacity so that you can always hold your setpoint no matter what, you end up with a really oversized system.

    What it boils down is that once you the Manual J load calculation, you correct for the way equipment capacity is rated at 80 degrees (most people want it to be more like 75, which derates equipment capacity). At that point, you have a BTU value, and you select a system that matches that cooling load. There are very few cases that justify fudging on the numbers, and I just don't see this as being one.

  12. #25
    Join Date
    Oct 2005
    Posts
    96
    If you go two stage variable speed you have the ability to slow down the fan speed on a system that is "slightly" oversized to reduce the cooling capacity and hence remove more moisture. I totally understand what your saying though that you have to be careful not to oversize your system. People that don't understand HVAC don't understand that biggger is not always better for the reasons you stated.

  13. #26
    If you like fast hot heat on cold days, you can use a gas furnace with a heat pump and have an outdoor thermostat that will cause the call to go to gas if the temp drops below a set point.

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